The present invention relates to a disc drive microactuator, and more particularly to a high resolution positioning mechanism for selectively moving a transducer portion of the slider radially with respect to circumferential data tracks of a rotatable disc.
The density of concentric data tracks on magnetic discs continues to increase (that is, the size of data tracks and radial spacing between data tracks are decreasing), requiring more precise radial positioning of the head. Conventionally, head positioning is accomplished by operating an actuator arm with a large-scale actuator motor, such as a voice coil motor, to position a head on a flexure at the end of the actuator arm. The large-scale motor lacks sufficient resolution and bandwidth to effectively accommodate high track-density discs. Thus, a high resolution head positioning mechanism is necessary to accommodate the more densely spaced tracks.
One promising design for high resolution head positioning involves employing a high resolution microactuator in addition to the conventional low resolution actuator motor, thereby effecting head positioning through dual-stage actuation. Various microactuator designs have been considered to accomplish high resolution head positioning, including piezoelectric, electromagnetic, electrostatic, capacitive, fluidic, and thermal actuators. Various locations for the microactuator have been suggested, including on the slider, on the gimbal, at the interface between the gimbal and the slider, and on the actuator arm, for example. However, the previous designs have had shortcomings that limited the effectiveness of the microactuator, such as substantial performance limitations or manufacturing complexities, which make the microactuator designs impractical. An effective microactuator design must provide high acceleration in positioning the head while also generating sufficiently large and accurate displacements to precisely move the head across several data tracks on the disc.
There is a need in the art for a microactuator design to provide high resolution head positioning with superior bandwidth performance characteristics that can be implemented by simple and readily available manufacturing processes.
The present invention is a slider assembly for selectively altering a position of a transducing head with respect to a track of a rotatable disc having a plurality of concentric tracks. A slider wafer is arranged to be supported by a disc drive support structure. A stator is bonded to the slider wafer, with the stator including at least one electrode. A rotor is bonded to the stator wafer, with the rotor having a frame portion bonded to the stator and a head-carrying portion attached to the frame portion by a flexible beam structure. The head-carrying portion of the rotor carries the transducing head, supports at least one rotor electrode adjacent to the at least one stator electrode, and is movable with respect to the frame portion of the rotor in response to a voltage difference between the at least one rotor electrode and the at least one stator electrode.
In accordance with the present invention, the slider assembly is fabricated by forming a slider body arranged to be supported by disc drive support structure, forming a stator, bonding the stator to the slider body, forming at least one stator electrode in the stator, forming a rotor, forming a transducing head on the rotor, forming at least one rotor electrode in the rotor, bonding the rotor to the stator, and forming a beam structure in the rotor, thereby forming a frame portion bonded to the stator and a head-carrying portion connected to the frame portion by the beam structure.